Health and Superfund

I belatedly happened across an interesting paper by Michael Greenstone. The Abstract summarizes the key finding:

We are the first to examine the effect of Superfund cleanups on infant health rather than focusing on proximity to a site. We study singleton births to mothers residing within 5km of a Superfund site between 1989-2003 in five large states. Our “difference in differences” approach compares birth outcomes before and after a site clean-up for mothers who live within 2,000 meters of the site and those who live between 2,000- 5,000 meters of a site. We find that proximity to a Superfund site before cleanup is associated with a 20 to 25% increase in the risk of congenital anomalies.

That’s a striking finding: a 20-25% increase in birth defects near Superfund sites prior to clean-up.

Greenstone is an MIT economist who can’t be accused of being an environmentalist cheerleader — for example, his most recent paper argues that cook stoves may not deliver their promised benefits to the global poor or to the environment. So the Superfund finding has a certain degree of credibility.

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Reader Comments

Like most of Greenston’e stuff, it’s an interesting paper. It is, however, worth quoting from the paper’s conclusions:

The finding of health benefits does not necessarily imply that it is in the public interest to continue the Superfund program in its current form. It might be more cost effective, for example, simply to ensure that people do not live near contaminated sites. Further research is clearly needed to determine whether the program is cost effective in improving health outcomes relative to possible alternative use of federal resources. Given the likelihood of a large heterogeneity in the toxicity level of the remaining sites, further research is also needed to determine how the expected benefits of the clean ups may vary across sites, as the program moves its focus from the sites with the highest levels of pollution to the sites with lower levels of pollution. . . .

A primary limitation of our study is that like many previous studies of hazardous waste sites we do not have a direct measure of exposure or the toxics that individuals were exposed to. Hence, our estimates cannot be used to identify the precise pathways or toxics through which proximity harms health. This is an important question for future research.

Like most of Greenston’e stuff, it’s an interesting paper. It is, however, worth quoting from the paper’s conclusions:

The finding of health benefits does not necessarily imply that it is in the public interest to continue the Superfund program in its current form. It might be more cost effective, for example, simply to ensure that people do not live near contaminated sites. Further research is clearly needed to determine whether the program is cost effective in improving health outcomes relative to possible alternative use of federal resources. Given the likelihood of a large heterogeneity in the toxicity level of the remaining sites, further research is also needed to determine how the expected benefits of the clean ups may vary across sites, as the program moves its focus from the sites with the highest levels of pollution to the sites with lower levels of pollution. . . .

A primary limitation of our study is that like many previous studies of hazardous waste sites we do not have a direct measure of exposure or the toxics that individuals were exposed to. Hence, our estimates cannot be used to identify the precise pathways or toxics through which proximity harms health. This is an important question for future research.